Polyurethanes are extremely versatile materials and have been used in a wide variety of applications such as foam insulation, car seats, paint coatings, and abrasion resistant coatings. Paint coating compositions are surface protective and/or decorative coatings which may be applied to substrates and allowed to dry or cure to form continuous protective and decorative films. Such coatings may be applied to a wide variety of substrates including metals, wood, plastics, and plaster. Important properties of the formed film include hardness and resistance to water.
Polyurethane dispersion polymers are an important class of binders for aqueous coating compositions, as they produce excellent properties, such as chemical and stain resistance, hardness and toughness in the solid coating.
Polyurethanes are also used in a wide variety of forms, for example non-cellular materials such as elastomers, and cellular materials such as low density flexible foams, high density flexible foams, and microcellular foams.
Polyurethanes, both in dispersion and non-dispersion forms, are also known to find use in adhesives, for example in deployment in the furniture industry.
EP0795572 is directed to the use of a polyester polyol, derived from terephthalic acid and adipic acid, to produce polyurethane foam for shoe soles.
WO 03/070801 describes microcellular polyurethane foams obtainable by reacting polyisocyanates with polyester, where the polyester is formed from a dimer fatty acid. In particular, this published document discloses use of dimer fatty acids of C18 fatty acid monomer with adipic acid and diethylene glycol to form the polyester, and use of 4,4′-diphenylmethane diisocyanate as a polyisocyanate to form the polyurethane,
WO 2004/056901 describes polyurethane based adhesives formed from polyisocyanates and polyols. In particular, this published document discloses use of dimer fatty acids of C18 fatty acid monomer with adipic acid and ethylene or propylene glycol to form the polyester, and use of a mixture of 2,4′- and 4,4′-diphenylmethane diisocyanate as a polyisocyanate for forming the polyurethane,
These known polyester based polyurethane compounds have a number of disadvantages, one being in relation to the sources of the individual building blocks. For example, the diol typically used in forming the polyester would be 1,6-hexanediol. However, this is prepared industrially by the hydrogenation of adipic acid. Production of (petrochemical-based) adipic acid and 1,6-hexanediol typically involves relatively large use of resources, and especially emission of nitrous oxide, resulting in a relatively large carbon footprint, which makes these components less environmentally friendly and therefore less desirable.
There is a growing need and desire to form polyesters and polyurethanes which can be synthesised from more renewable biobased components, and which have equivalent or improved physical properties in comparison to existing polyesters and polyurethanes as discussed herein.